require('script-loader!file-saver');
import XLSX from 'xlsx'
import Workbook from './Workbook'

class Excel {
  static generateArray(table) {
    let out = [];
    let rows = table.querySelectorAll('tr');
    let ranges = [];
    for (let R = 0; R < rows.length; ++R) {
      let outRow = [];
      let row = rows[R];
      let columns = row.querySelectorAll('td');
      for (let C = 0; C < columns.length; ++C) {
        let cell = columns[C];
        let colspan = cell.getAttribute('colspan');
        let rowspan = cell.getAttribute('rowspan');
        let cellValue = cell.innerText;
        if (cellValue !== "" && cellValue == +cellValue) cellValue = +cellValue;

        //Skip ranges
        ranges.forEach(function (range) {
          if (R >= range.s.r && R <= range.e.r && outRow.length >= range.s.c && outRow.length <= range.e.c) {
            for (let i = 0; i <= range.e.c - range.s.c; ++i) outRow.push(null);
          }
        });

        //Handle Row Span
        if (rowspan || colspan) {
          rowspan = rowspan || 1;
          colspan = colspan || 1;
          ranges.push({
            s: {
              r: R,
              c: outRow.length
            },
            e: {
              r: R + rowspan - 1,
              c: outRow.length + colspan - 1
            }
          });
        };

        //Handle Value
        outRow.push(cellValue !== "" ? cellValue : null);

        //Handle Colspan
        if (colspan)
          for (let k = 0; k < colspan - 1; ++k) outRow.push(null);
      }
      out.push(outRow);
    }
    return [out, ranges];
  }

  static datenum(v, date1904) {
    if (date1904) v += 1462;
    let epoch = Date.parse(v);
    return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000);
  }

  static sheet_from_array_of_arrays(data, opts) {
    let ws = {};
    let range = {
      s: {
        c: 10000000,
        r: 10000000
      },
      e: {
        c: 0,
        r: 0
      }
    };
    for (let R = 0; R != data.length; ++R) {
      for (let C = 0; C != data[R].length; ++C) {
        if (range.s.r > R) range.s.r = R;
        if (range.s.c > C) range.s.c = C;
        if (range.e.r < R) range.e.r = R;
        if (range.e.c < C) range.e.c = C;
        let cell = {
          v: data[R][C]
        };
        if (cell.v == null) continue;
        let cell_ref = XLSX.utils.encode_cell({
          c: C,
          r: R
        });

        if (typeof cell.v === 'number') cell.t = 'n';
        else if (typeof cell.v === 'boolean') cell.t = 'b';
        else if (cell.v instanceof Date) {
          cell.t = 'n';
          cell.z = XLSX.SSF._table[14];
          cell.v = datenum(cell.v);
        } else cell.t = 's';

        ws[cell_ref] = cell;
      }
    }
    if (range.s.c < 10000000) ws['!ref'] = XLSX.utils.encode_range(range);
    return ws;
  }

  static s2ab(s) {
    let buf = new ArrayBuffer(s.length);
    let view = new Uint8Array(buf);
    for (let i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xFF;
    return buf;
  }

  static export_table_to_excel(id) {
    let theTable = document.getElementById(id);
    let oo = generateArray(theTable);
    let ranges = oo[1];

    /* original data */
    let data = oo[0];
    let ws_name = "SheetJS";

    let wb = new Workbook(),
      ws = sheet_from_array_of_arrays(data);

    /* add ranges to worksheet */
    // ws['!cols'] = ['apple', 'banan'];
    ws['!merges'] = ranges;

    /* add worksheet to workbook */
    wb.SheetNames.push(ws_name);
    wb.Sheets[ws_name] = ws;

    let wbout = XLSX.write(wb, {
      bookType: 'xlsx',
      bookSST: false,
      type: 'binary'
    });

    saveAs(new Blob([this.s2ab(wbout)], {
      type: "application/octet-stream"
    }), "test.xlsx")
  }


  static loadExcel(filePath) {
    var excelData = [];
    //胜利ar excelFile = req.files.file.data;
    //const workbook = XLSX.read(excelFile);
    var workbook = XLSX.readFile(filePath);
    var sheetNames = workbook.SheetNames;
   
    for (var sheet in workbook.Sheets) {
      if (workbook.Sheets.hasOwnProperty(sheet)) {
        //胜利ar fromTo = workbook.Sheets[sheet]['!ref'];
        excelData = excelData.concat(XLSX.utils.sheet_to_json(workbook.Sheets[sheet])); //解析excel文件得到数据
      }
    }
    
  }


  static export_json_to_excel({
    multiHeader = [],
    header,
    data,
    filename,
    merges = [],
    autoWidth = true,
    bookType = 'xlsx'
  } = {}) {
    /* original data */
    filename = filename || 'excel-list'
    data = [...data]
    data.unshift(header);

    for (let i = multiHeader.length - 1; i > -1; i--) {
      data.unshift(multiHeader[i])
    }

    let ws_name = "SheetJS";
    let wb = new Workbook(),
      ws = this.sheet_from_array_of_arrays(data);

    if (merges.length > 0) {
      if (!ws['!merges']) ws['!merges'] = [];
      merges.forEach(item => {
        ws['!merges'].push(XLSX.utils.decode_range(item))
      })
    }

    if (autoWidth) {
      /*设置worksheet每列的最大宽度*/
      const colWidth = data.map(row => row.map(val => {
        /*先判断是否为null/undefined*/
        if (val == null) {
          return {
            'wch': 10
          };
        }
        /*再判断是否为中文*/
        else if (val.toString().charCodeAt(0) > 255) {
          return {
            'wch': val.toString().length * 2
          };
        } else {
          return {
            'wch': val.toString().length
          };
        }
      }))
      /*以第一行为初始值*/
      let result = colWidth[0];
      for (let i = 1; i < colWidth.length; i++) {
        for (let j = 0; j < colWidth[i].length; j++) {
          if (result[j]['wch'] < colWidth[i][j]['wch']) {
            result[j]['wch'] = colWidth[i][j]['wch'];
          }
        }
      }
      ws['!cols'] = result;
    }

    /* add worksheet to workbook */
    wb.SheetNames.push(ws_name);
    wb.Sheets[ws_name] = ws;

    let wbout = XLSX.write(wb, {
      bookType: bookType,
      bookSST: false,
      type: 'binary'
    });
    saveAs(new Blob([this.s2ab(wbout)], {
      type: "application/octet-stream"
    }), `${filename}.${bookType}`);
  }
}
export default Excel;
